Brother FAX-T104 Series - Manual (Page 21)

Introduction
1 - 8
Fax tones and handshake
When someone is sending a fax, the fax machine sends fax calling
tones (CNG tones). These are quiet, intermittent beeps every
4-seconds. You’ll hear them after you dial and press Fax Start and
they will continue for about 60 seconds after dialling. During that
time, the sending machine must begin the “handshake” with the
receiving machine.
Each time you use automatic procedures to send a fax, you are
sending CNG tones over the phone line. You’ll soon learn to listen
for these quiet beeps each time you answer a phone on your fax
line, so you will know if you are receiving a fax message.
The receiving fax responds with fax receiving tones, which are
loud, chirping sounds. A receiving fax chirps for about 40 seconds
over the phone line, and the LCD shows RECEIVE.
If the fax machine is set to the FAX ONLY mode, it will answer every
call automatically with fax receiving tones. If the other person
hangs up, the fax machine will continue to send the “chirps” for
about 40 seconds, and the LCD continues to show RECEIVE. To
cancel the receiving, press Stop/Exit.
The fax ‘handshake’ is the time in which the sending machine’s
CNG tones and the receiving machines “chirps” overlap. This must
be for at least 2 to 4 seconds, so the fax machines can understand
how each is sending and receiving the fax. The handshake cannot
begin until the call is answered, and the CNG tones only last for
about 60 seconds after the number is dialled. So it is important for
the receiving machine to answer the call in as few rings as
possible.
ECM (Error Correction Mode)
The Error Correction Mode (ECM) is a way for the fax machine to
check a fax transmission while it is in progress. ECM transmissions
are only possible between machines that both have this feature. If
they do, you may send and receive fax messages that are
continuously being checked by the fax machine.
The fax machine must have enough memory for this feature to
work.
When you have an external Telephone Answering Device
(TAD) on your fax line, your TAD will decide the number of
rings before the call is answered.
Pay special attention to the directions for connecting a TAD in
this chapter. (See Connecting an external telephone
answering device (TAD) on page 1-9.)